/*
** $Id: loslib.c,v 1.65 2016/07/18 17:58:58 roberto Exp $
** Standard Operating System library
** See Copyright Notice in lua.h
*/

#define loslib_c
#define LUA_LIB

#include "lprefix.h"


#include <errno.h>
#include <locale.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"


/*
** {==================================================================
** List of valid conversion specifiers for the 'strftime' function;
** options are grouped by length; group of length 2 start with '||'.
** ===================================================================
*/
#if !defined(LUA_STRFTIMEOPTIONS)   /* { */

/* options for ANSI C 89 (only 1-char options) */
#define L_STRFTIMEC89       "aAbBcdHIjmMpSUwWxXyYZ%"

/* options for ISO C 99 and POSIX */
#define L_STRFTIMEC99 "aAbBcCdDeFgGhHIjmMnprRStTuUVwWxXyYzZ%" \
    "||" "EcECExEXEyEY" "OdOeOHOIOmOMOSOuOUOVOwOWOy"  /* two-char options */

/* options for Windows */
#define L_STRFTIMEWIN "aAbBcdHIjmMpSUwWxXyYzZ%" \
    "||" "#c#x#d#H#I#j#m#M#S#U#w#W#y#Y"  /* two-char options */

#if defined(LUA_USE_WINDOWS)
#define LUA_STRFTIMEOPTIONS L_STRFTIMEWIN
#elif defined(LUA_USE_C89)
#define LUA_STRFTIMEOPTIONS L_STRFTIMEC89
#else  /* C99 specification */
#define LUA_STRFTIMEOPTIONS L_STRFTIMEC99
#endif

#endif                  /* } */
/* }================================================================== */


/*
** {==================================================================
** Configuration for time-related stuff
** ===================================================================
*/

#if !defined(l_time_t)      /* { */
/*
** type to represent time_t in Lua
*/
#define l_timet         lua_Integer
#define l_pushtime(L,t)     lua_pushinteger(L,(lua_Integer)(t))

static time_t l_checktime( lua_State* L, int arg ) {
    lua_Integer t = luaL_checkinteger( L, arg );
    luaL_argcheck( L, ( time_t )t == t, arg, "time out-of-bounds" );
    return ( time_t )t;
}

#endif              /* } */


#if !defined(l_gmtime)      /* { */
/*
** By default, Lua uses gmtime/localtime, except when POSIX is available,
** where it uses gmtime_r/localtime_r
*/

#if defined(LUA_USE_POSIX)  /* { */

#define l_gmtime(t,r)       gmtime_r(t,r)
#define l_localtime(t,r)    localtime_r(t,r)

#else               /* }{ */

/* ISO C definitions */
#define l_gmtime(t,r)       ((void)(r)->tm_sec, gmtime(t))
#define l_localtime(t,r)    ((void)(r)->tm_sec, localtime(t))

#endif              /* } */

#endif              /* } */

/* }================================================================== */


/*
** {==================================================================
** Configuration for 'tmpnam':
** By default, Lua uses tmpnam except when POSIX is available, where
** it uses mkstemp.
** ===================================================================
*/
#if !defined(lua_tmpnam)    /* { */

#if defined(LUA_USE_POSIX)  /* { */

#include <unistd.h>

#define LUA_TMPNAMBUFSIZE   32

#if !defined(LUA_TMPNAMTEMPLATE)
#define LUA_TMPNAMTEMPLATE  "/tmp/lua_XXXXXX"
#endif

#define lua_tmpnam(b,e) { \
        strcpy(b, LUA_TMPNAMTEMPLATE); \
        e = mkstemp(b); \
        if (e != -1) close(e); \
        e = (e == -1); }

#else               /* }{ */

/* ISO C definitions */
#define LUA_TMPNAMBUFSIZE   L_tmpnam
#define lua_tmpnam(b,e)     { e = (tmpnam(b) == NULL); }

#endif              /* } */

#endif              /* } */
/* }================================================================== */




static int os_execute( lua_State* L ) {
    const char* cmd = luaL_optstring( L, 1, NULL );
    int stat = system( cmd );

    if ( cmd != NULL ) {
        return luaL_execresult( L, stat );
    }
    else {
        lua_pushboolean( L, stat ); /* true if there is a shell */
        return 1;
    }
}


static int os_remove( lua_State* L ) {
    const char* filename = luaL_checkstring( L, 1 );
    return luaL_fileresult( L, remove( filename ) == 0, filename );
}


static int os_rename( lua_State* L ) {
    const char* fromname = luaL_checkstring( L, 1 );
    const char* toname = luaL_checkstring( L, 2 );
    return luaL_fileresult( L, rename( fromname, toname ) == 0, NULL );
}


static int os_tmpname( lua_State* L ) {
    char buff[LUA_TMPNAMBUFSIZE];
    int err;
    lua_tmpnam( buff, err );

    if ( err ) {
        return luaL_error( L, "unable to generate a unique filename" );
    }

    lua_pushstring( L, buff );
    return 1;
}


static int os_getenv( lua_State* L ) {
    lua_pushstring( L, getenv( luaL_checkstring( L, 1 ) ) ); /* if NULL push nil */
    return 1;
}


static int os_clock( lua_State* L ) {
    lua_pushnumber( L, ( ( lua_Number )clock() ) / ( lua_Number )CLOCKS_PER_SEC );
    return 1;
}


/*
** {======================================================
** Time/Date operations
** { year=%Y, month=%m, day=%d, hour=%H, min=%M, sec=%S,
**   wday=%w+1, yday=%j, isdst=? }
** =======================================================
*/

static void setfield( lua_State* L, const char* key, int value ) {
    lua_pushinteger( L, value );
    lua_setfield( L, -2, key );
}

static void setboolfield( lua_State* L, const char* key, int value ) {
    if ( value < 0 ) { /* undefined? */
        return;    /* does not set field */
    }

    lua_pushboolean( L, value );
    lua_setfield( L, -2, key );
}


/*
** Set all fields from structure 'tm' in the table on top of the stack
*/
static void setallfields( lua_State* L, struct tm* stm ) {
    setfield( L, "sec", stm->tm_sec );
    setfield( L, "min", stm->tm_min );
    setfield( L, "hour", stm->tm_hour );
    setfield( L, "day", stm->tm_mday );
    setfield( L, "month", stm->tm_mon + 1 );
    setfield( L, "year", stm->tm_year + 1900 );
    setfield( L, "wday", stm->tm_wday + 1 );
    setfield( L, "yday", stm->tm_yday + 1 );
    setboolfield( L, "isdst", stm->tm_isdst );
}


static int getboolfield( lua_State* L, const char* key ) {
    int res;
    res = ( lua_getfield( L, -1, key ) == LUA_TNIL ) ? -1 : lua_toboolean( L, -1 );
    lua_pop( L, 1 );
    return res;
}


/* maximum value for date fields (to avoid arithmetic overflows with 'int') */
#if !defined(L_MAXDATEFIELD)
#define L_MAXDATEFIELD  (INT_MAX / 2)
#endif

static int getfield( lua_State* L, const char* key, int d, int delta ) {
    int isnum;
    int t = lua_getfield( L, -1, key ); /* get field and its type */
    lua_Integer res = lua_tointegerx( L, -1, &isnum );

    if ( !isnum ) { /* field is not an integer? */
        if ( t != LUA_TNIL ) { /* some other value? */
            return luaL_error( L, "field '%s' is not an integer", key );
        }
        else if ( d < 0 ) { /* absent field; no default? */
            return luaL_error( L, "field '%s' missing in date table", key );
        }

        res = d;
    }
    else {
        if ( !( -L_MAXDATEFIELD <= res && res <= L_MAXDATEFIELD ) ) {
            return luaL_error( L, "field '%s' is out-of-bound", key );
        }

        res -= delta;
    }

    lua_pop( L, 1 );
    return ( int )res;
}


static const char* checkoption( lua_State* L, const char* conv,
                                ptrdiff_t convlen, char* buff ) {
    const char* option = LUA_STRFTIMEOPTIONS;
    int oplen = 1;  /* length of options being checked */

    for ( ; *option != '\0' && oplen <= convlen; option += oplen ) {
        if ( *option == '|' ) { /* next block? */
            oplen++;    /* will check options with next length (+1) */
        }
        else if ( memcmp( conv, option, oplen ) == 0 ) { /* match? */
            memcpy( buff, conv, oplen ); /* copy valid option to buffer */
            buff[oplen] = '\0';
            return conv + oplen;  /* return next item */
        }
    }

    luaL_argerror( L, 1,
                   lua_pushfstring( L, "invalid conversion specifier '%%%s'", conv ) );
    return conv;  /* to avoid warnings */
}


/* maximum size for an individual 'strftime' item */
#define SIZETIMEFMT 250


static int os_date( lua_State* L ) {
    size_t slen;
    const char* s = luaL_optlstring( L, 1, "%c", &slen );
    time_t t = luaL_opt( L, l_checktime, 2, time( NULL ) );
    const char* se = s + slen;  /* 's' end */
    struct tm tmr, *stm;

    if ( *s == '!' ) { /* UTC? */
        stm = l_gmtime( &t, &tmr );
        s++;  /* skip '!' */
    }
    else {
        stm = l_localtime( &t, &tmr );
    }

    if ( stm == NULL ) { /* invalid date? */
        luaL_error( L, "time result cannot be represented in this installation" );
    }

    if ( strcmp( s, "*t" ) == 0 ) {
        lua_createtable( L, 0, 9 ); /* 9 = number of fields */
        setallfields( L, stm );
    }
    else {
        char cc[4];  /* buffer for individual conversion specifiers */
        luaL_Buffer b;
        cc[0] = '%';
        luaL_buffinit( L, &b );

        while ( s < se ) {
            if ( *s != '%' ) { /* not a conversion specifier? */
                luaL_addchar( &b, *s++ );
            }
            else {
                size_t reslen;
                char* buff = luaL_prepbuffsize( &b, SIZETIMEFMT );
                s++;  /* skip '%' */
                s = checkoption( L, s, se - s, cc + 1 ); /* copy specifier to 'cc' */
                reslen = strftime( buff, SIZETIMEFMT, cc, stm );
                luaL_addsize( &b, reslen );
            }
        }

        luaL_pushresult( &b );
    }

    return 1;
}


static int os_time( lua_State* L ) {
    time_t t;

    if ( lua_isnoneornil( L, 1 ) ) { /* called without args? */
        t = time( NULL );    /* get current time */
    }
    else {
        struct tm ts;
        luaL_checktype( L, 1, LUA_TTABLE );
        lua_settop( L, 1 ); /* make sure table is at the top */
        ts.tm_sec = getfield( L, "sec", 0, 0 );
        ts.tm_min = getfield( L, "min", 0, 0 );
        ts.tm_hour = getfield( L, "hour", 12, 0 );
        ts.tm_mday = getfield( L, "day", -1, 0 );
        ts.tm_mon = getfield( L, "month", -1, 1 );
        ts.tm_year = getfield( L, "year", -1, 1900 );
        ts.tm_isdst = getboolfield( L, "isdst" );
        t = mktime( &ts );
        setallfields( L, &ts ); /* update fields with normalized values */
    }

    if ( t != ( time_t )( l_timet )t || t == ( time_t )( -1 ) ) {
        luaL_error( L, "time result cannot be represented in this installation" );
    }

    l_pushtime( L, t );
    return 1;
}


static int os_difftime( lua_State* L ) {
    time_t t1 = l_checktime( L, 1 );
    time_t t2 = l_checktime( L, 2 );
    lua_pushnumber( L, ( lua_Number )difftime( t1, t2 ) );
    return 1;
}

/* }====================================================== */


static int os_setlocale( lua_State* L ) {
    static const int cat[] = {LC_ALL, LC_COLLATE, LC_CTYPE, LC_MONETARY,
                              LC_NUMERIC, LC_TIME
                             };
    static const char* const catnames[] = {"all", "collate", "ctype", "monetary",
                                           "numeric", "time", NULL
                                          };
    const char* l = luaL_optstring( L, 1, NULL );
    int op = luaL_checkoption( L, 2, "all", catnames );
    lua_pushstring( L, setlocale( cat[op], l ) );
    return 1;
}


static int os_exit( lua_State* L ) {
    int status;

    if ( lua_isboolean( L, 1 ) ) {
        status = ( lua_toboolean( L, 1 ) ? EXIT_SUCCESS : EXIT_FAILURE );
    }
    else {
        status = ( int )luaL_optinteger( L, 1, EXIT_SUCCESS );
    }

    if ( lua_toboolean( L, 2 ) ) {
        lua_close( L );
    }

    if ( L ) {
        exit( status );    /* 'if' to avoid warnings for unreachable 'return' */
    }

    return 0;
}


static const luaL_Reg syslib[] = {
    {"clock",     os_clock},
    {"date",      os_date},
    {"difftime",  os_difftime},
    {"execute",   os_execute},
    {"exit",      os_exit},
    {"getenv",    os_getenv},
    {"remove",    os_remove},
    {"rename",    os_rename},
    {"setlocale", os_setlocale},
    {"time",      os_time},
    {"tmpname",   os_tmpname},
    {NULL, NULL}
};

/* }====================================================== */



LUAMOD_API int luaopen_os( lua_State* L ) {
    luaL_newlib( L, syslib );
    return 1;
}

